Question: William ate 5 slices of cake. Kevin ate 4 slices. If William ate $\dfrac{5}{10}$ of the cake, what fraction of the cake is remaining?
Answer: If 5 slices represent $\dfrac{5}{10}$ of the cake, there must have been a total of 10 slices. $\text{fraction of cake remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 9 slices, which leaves 1 out of 10 slices remaining. There is $\dfrac{1}{10}$ of the cake remaining.